Conventional lithium-ion batteries reach their limits, primarily due to their cathodes. While stabilizing layers form on the anode during charging, the material on the cathode side decomposes over time. This process releases oxygen and dissolves metals from the structure, which continually reduces the performance of a battery.
A team led by Professor Chunsheng Wang published a method to stop this decay in the journal Nature Chemistry. The scientists controlled the chemical reactions on the electrolyte so precisely that a protective layer was created directly on the cathode. They increased the reduction potential to values between 2.4 and 4.2 volts.
The new protective layer prevents transition metals from dissolving and stabilizes the chemical processes inside the cell. In laboratory tests, the researchers found an almost constant capacity over 200 charging cycles. This allows more powerful and longer-lasting batteries to be built.
Cathode protective layer increases battery performance and lifespan
Electric aviation and space travel could particularly benefit. In these areas, batteries require a high energy density and a low weight. Since the researchers only made minimal interventions in the functioning of the electrolytes, the technology can be integrated into current production systems.
In parallel with the improvements in lithium batteries, the laboratory developed a concept for batteries based on sodium metal. In the journal Nature Chemistry, the scientists describe an electrolyte that does not require critical chemicals. Sodium offers a sustainable alternative because it occurs much more frequently in the earth’s crust than lithium.
The metal sodium exists all over the world in common mineral deposits or dissolved in seawater. This high availability eliminates supply risks and raw material shortages that often burden the production of lithium-ion batteries. Manufacturers could thereby reduce the costs of storage systems that temporarily store electricity from wind and solar energy for the grid.
The researchers completely avoid using fluorinated solvents in their new formula. These substances pose a burden on the environment during production and subsequent disposal and pose ecological risks. By using a sustainable electrolyte mixture, the scientists reduced these risks and made it easier to recycle the battery components.
Protection against internal short circuits
A central problem when using sodium metal are so-called dendrites. These are harmful, needle-like structures made of metal that grow uncontrollably through the cell during operation. They pierce the inner layers, causing short circuits and can lead to premature battery failure or malfunction.
The adapted molecular structure of the electrolytes suppresses this growth. In addition, the chemical composition prevents toxic or flammable gases from being produced inside the cell. This means that sodium batteries achieve a level of safety and performance that makes them suitable for use in modern electric cars.
The scientists emphasize that these adaptations can be integrated into existing industrial manufacturing processes without much effort. Since sodium is evenly distributed across all continents, the technology makes the energy transition less dependent on global supply chains. The laboratory is now planning further experiments to accelerate the market readiness of these environmentally friendly storage solutions.
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